1. Field of the Invention
The present invention relates to a canned pump, more specifically, to a canned pump capable of obtaining good cooling capability and minimizing manufacturing cost.
2. Description of the Prior Art
Hitherto, a conventional canned pump is consisted to assemble a driving circuit for driving the pump in a housing and to cover the driving circuit by a lower case. A means for cooling a MOS type FET (Metal Oxide Semiconductor type Field Effect Transistor) which is a portion of the driving circuit, an end cover for covering the MOS type FET is used as a heat sink for cooling the MOS type FET.
Therefore, in the conventional canned pump, the MOS type FET is fixed to the end cover by means of screws and an electrical lead line of the MOS type FET is soldered to a circuit substrate of the driving circuit to not apply a stress to the soldered part after the circuit substrate is fixed to the end cover (see Japanese Laid-Open Publication No.2001-304198 as the similar art).
In such a conventional canned pump, it is necessary to make the end cover by a material having good heat conductance, for example, aluminum since the end cover is used as the heat sink.
However, since the end cover has a cup-like shape, it is difficult to produce it by extruding aluminum.
If the end cover is produced by die-casting of aluminum, deterioration of heat conductivity is caused.
If the end cover is produced by forging of aluminum which has good heat conductance, manufacturing cost is increased.
On the other hand, in the aforementioned conventional canned pump, a sequence of process of soldering the electrical lead line of the MOS type PET is also limited.
Under such circumstances, a further improvement, in the conventional canned pump is required.